Naturally occurring BRCA2 alternative mRNA splicing events in clinically relevant samples

Area of Science:

• Genetics
• Molecular Biology
• Cancer Research

Background:

• BRCA1 and BRCA2 are key tumor suppressor genes linked to hereditary breast and ovarian cancers.
• Genetic testing for BRCA1/2 can yield variants of uncertain significance, potentially impacting gene function through splicing.
• mRNA analysis is used to interpret variant significance but can be complicated by natural alternative transcripts.

Purpose of the Study:

• To characterize the spectrum of naturally occurring BRCA2 mRNA alternate-splicing events.
• To differentiate normal splicing from splicing defects caused by mutations.
• To aid in the accurate interpretation of BRCA2 variants.

Main Methods:

• mRNA was isolated from blood and breast tissue cell lines.
• cDNA was generated and amplified to represent BRCA2 alternate splice sites.
• Capillary or agarose gel electrophoresis and sequencing were used for visualization and analysis.

Main Results:

• A total of 24 distinct BRCA2 mRNA alternate-splicing events were identified.
• These events were observed in lymphoblastoid cell lines and both cancerous and non-cancerous breast cell lines.

Conclusions:

• Naturally occurring alternate splicing in BRCA2 contributes to observed cDNA fragments in mutation assays.
• Careful consideration is needed when attributing alternate splicing events to potential splicing mutations.
• Distinguishing natural splicing from mutation-induced splicing is vital for accurate genetic variant interpretation.